There was this nagging memory of some thought some time ago that Jesus was the "pillar of fire" or something like that. Took me a bit, but I finally found the one reference I was looking for.
21 Jehovah also uses angelic representatives to teach, including his Firstborn, “the Word.” (John 1:1-3) Although Jehovah could have spoken directly to his perfect human son, Adam, in the garden of Eden, likely he used the prehuman Jesus to speak for Him. (Genesis 2:16, 17) This one was probably “the angel of the true God who was going ahead of the camp of Israel” and regarding whom Jehovah commanded: “Obey his voice.” (Exodus 14:19; 23:20, 21) No doubt the prehuman Jesus was also the “prince of the army of Jehovah” who appeared to Joshua to strengthen him. (Joshua 5:14, 15) Jehovah also uses other angels to impart his teachings, such as those he used to deliver his Law to Moses.—Exodus 20:1; Galatians 3:19; Hebrews 2:2, 3.
w95 8/1 p. 13 par. 21
Then I searched for "prehuman Jesus" and found this:
As the history of Israel unfurled, the Word observed Satan’s attempts to turn humans away from pure worship. Following the Exodus from Egypt, God told Israel through Moses: “Here I am sending an angel ahead of you to keep you on the road and to bring you into the place that I have prepared. Watch yourself because of him and obey his voice. Do not behave rebelliously against him, for he will not pardon your transgression; because my name is within him.” (Exodus 23:20, 21) Who was this angel? Likely, the prehuman Jesus.
w98 6/15 p. 23
And:
•23:20-23—Who was the angel mentioned here, and how was it that Jehovah’s name was “within him”?
Angels other than the prehuman Jesus Christ were used to transmit God’s law to Moses. (John 1:1-3, 14; Hebrews 2:2, 3) But it is reasonable to conclude that the angel of whom Jehovah said “my name is within him” was Jesus in his prehuman form. He was used to guide the Israelites on their way to the Promised Land. (1 Corinthians 10:1-4) Jesus, whose name means “Salvation of Jehovah,” is the principal one that upholds and vindicates his Father’s name.w83 10/15 p. 31
And:
What “things” did Isaiah say “because he saw his glory”? Well, John quotes Isaiah here twice, first quoting Isaiah 53:1 concerning the “arm of Jehovah” and then quoting Isaiah 6:10 concerning the temple vision. At Isaiah 53:1 the “arm of Jehovah” is Christ Jesus. At Isaiah 6:10 the speaker at the temple is Jehovah, but he includes his Son with him when he says: “Who will go for us?” that is, for me and my Son. Thus we see that the prehuman Jesus was associated with Jehovah in his glory at the temple, and hence John could rightly say Isaiah here saw his glory and spoke about him, “the arm of Jehovah.” Certainly Jesus the Greater Isaiah had not sent himself, but Jehovah at the temple did so, for John here applies Isaiah 6:10 to Jesus as the Sent One toward whom this prophecy was first fulfilled, after Jesus had ridden into Jerusalem and offered himself as King and had cleansed the temple. At that time Jesus was not in “his glory”, but the Jewish leaders had vilified him and had conspired to kill him.
w51 4/1 p. 216
There's probably more, but it's not something that was discussed all that much that I can recall.